Artificial



UNITED STATES LPATENT OFFICE.

BENJN. F. PALMER, 0F MEREDITI-I, NEW HAMPSHIRE.

ARTIFICIAL LEG.

Specification of Letters Patent No. 6,122, dated February 20, 1849.

To all whom t may concern.'

Ee it known that I, BENJAMIN F. PALMER, of Meredith, in the State of NewHampshire, have invented sundry new and useful Improvements inArtificial Legs; and I do herebjT declare that the following is a full,clear, and exact description thereof, reference being had to theaccompanying drawings, which form a part of this specification.

First, to the knee bolt of my artificial leg, in the interior of thelimb, I fasten an arm O Figures 3 and 4 which is in a horizontalposition, (usually pointing to the front) when the lower part of thelimb is in a vertical position. To the projecting end of this arm O isfastened, by means of a gut-cord, or otherwise, a coiled spring as shownat I); or in lieu of the coiled spring an elastic substance, strap orcord, `oran elliptic spring may be used. The end of this spring notattached to the gut-cord is fastened, in any convenient manner, to thepart of the limb above the aforesaid arm, and at any convenient distancefrom it, dependent upon the place at which the natural limb has beenamputated, but always at such a point that the cord which connects itwith the arm 0, shall be at right angles with that arm, when the limb isextended, but in a line parallel with it when the limb is flexed to aright angle at the knee joint. Thus arranged, it facilitates the motionabout the articulation, in cases where the stump of the natural thigh isshort, but will not act upon the foot and leg so as to throw themforward, when the wearer wishes them to remain flexed at the knee. Thestrain on the spring P may be increased or diminished by means of a cordfastened to the upper end, which may unite it to the socket, S whichreceives the stump of the amputated leg.

Second. In lieu of the elliptic spring in the bottom of the foot asrepresented at 7c in my original specification and drawing Fig. 2, I nowuse a coiled spring Q Figs. 3 and 4 wound around a bolt g. This springis formed by looping a piece of wire at the center to form an arm r, ofthe spring, proj ecting downward and on the posterior side of the boltg. The two ends of the wire thus looped are then wound around the bolt g(one on each side of the central loop,) until a sitflicient number ofturns has been made; they are then brought from below upward on theposterior side of the bolt, where they are recurved downward as seen ats, then bent toward each other and twisted together forming a loop towhich is connected the gut cord t. The office of this posterior arm s ofthe spring Q is to elevate the front part of the foot while that of thearm r extending downward as above described, is intended to depress orextend, by means of the cord c, the toes-when flexed upward as intreading with the front partof the foot.

Third. I place near the part of the artificial leg corresponding withthe ankle joint a bolt represented at w Fig. 3 which bolt serves as astop to the heel when elevated to its greatest height. The said bolt orstop is so placed as not to interfere with the cord of the heel F asseen in Fig. 2 of my original specifications.

Fourth. I form the concave-convex joint of the toes in my improvedartificial leg in the following manner. At the point- Figs. 3 5 and 6, ahorizontal hole is bored quite across the foo-t, through which is passeda wire, each end of which is then'bent forward at right angles, and incavities on the sides of the foot widening outward to allow of a slightmotion of the two ends of the wire up and down. Through the artificialtoe piece are bored two holes to receive the two ends of the wire justdescribed. These holes run horizontally or parallel with the `directionsof the toes, nearly to their ex tremities. The ends of the wires arethen bent downward and recurved backward over a pivot or pivots passingacross the toes, and the ends are depressed into, and retained ingrooves formed in the under side of the toepiece to receive them, asseen in Figs. 5 and 6.

"What I claim as my invention and desire to secure by Letters Patent arel. The combination of the horizontal arm with the knee bolt, connectedwith a cord and spring in suoli a manner as to possess a varyingtendency to extend the flexed limb according to the posit-ion of thesame, substantially as herein specified and described.

2. I claim the use of a combination of the double-coiled recurved footspring, with a boltand with downward and backward prothe said toe-pieceis operated on by the cord jeeting arms, acting at once to fiex the foote and spring Q to extend it in the manner 10 and t0 extend the toes, asherin set orthh and for the purposes herein set forth.

3. I claim the use of a com inaton of t e vT 1 stop bolt, with a movableheel as herein BEAJ li PALMER specified. o

4. I claim the manner herein described of connecting the toe-piece withthe foot, When Vitnesses Z. C. Roms, WARRIOR GUNSTALL.

